Cjc-1295 with dac

The defining feature of CJC-1295 with DAC is not what it does — it's how long it does it. Where unmodified growth hormone-releasing hormone (GHRH) lasts minutes in circulation, this synthetic analog persists for days, fundamentally changing how the compound behaves in vivo. That persistence comes from a single structural modification that binds the peptide to serum albumin, and it's the same modification that explains why human data remains sparse and why researchers distinguish sharply between "CJC-1295 with DAC" and the shorter-acting variant without it.

A 30-Amino-Acid GHRH Analog Engineered for Albumin Binding

CJC-1295 DAC is a 30-residue synthetic peptide modeled on the first 29 amino acids of human growth hormone-releasing hormone (hGRRH 1-29), with four amino acid substitutions to increase stability and a fifth critical modification: a Drug Affinity Complex (DAC) group attached to the lysine at position 16. The DAC group is a reactive chemical linker (maleimidoproprionic acid) that forms a covalent bond with circulating albumin after subcutaneous injection.

The peptide was developed in the early 2000s by ConjuChem Biotechnologies (later Biotech Growth Partners) as a long-acting GHRH analog intended for growth hormone deficiency. The amino acid substitutions — including Ala2, Gln8, Ala15, and Leu27 — protect the peptide from dipeptidyl peptidase-IV (DPP-IV) degradation and enzymatic cleavage at the N-terminus, vulnerabilities that limit the half-life of native GHRH to under 10 minutes.

The addition of the DAC group extends the effective half-life to approximately 6–8 days in humans, based on pharmacokinetic data from a Phase I/II trial published in 2004. That same trial measured plasma growth hormone and IGF-1 elevation over weeks, not hours. The molecular weight is 3647.28 Da, making it a mid-sized peptide, large enough to require subcutaneous injection but small enough for straightforward synthesis.

How DAC-Mediated Albumin Binding Sustains GHRH Receptor Activation

CJC-1295 DAC binds to the growth hormone-releasing hormone receptor (GHRH-R), a class B1 G protein-coupled receptor (GPCR) on somatotroph cells in the anterior pituitary. Upon binding, the receptor couples to the stimulatory G protein (Gs), activating adenylyl cyclase and increasing intracellular cyclic AMP (cAMP). Elevated cAMP activates protein kinase A (PKA), which phosphorylates transcription factors including CREB (cAMP response element-binding protein). CREB translocates to the nucleus and upregulates transcription of the growth hormone gene (GH1), leading to increased synthesis and pulsatile secretion of growth hormone into circulation.

The critical difference is duration. Native GHRH produces a sharp, transient rise in growth hormone that peaks within minutes and returns to baseline within an hour. CJC-1295 DAC, by virtue of its albumin binding, maintains steady-state receptor occupancy for days. This transforms the secretion pattern from discrete pulses to a sustained, wave-like elevation. The compound does not bypass the natural negative feedback loop — somatostatin still inhibits GHRH-R signaling — but it extends the window during which the receptor remains activated.

Growth hormone released from the pituitary travels to the liver, where it stimulates synthesis and secretion of insulin-like growth factor 1 (IGF-1). IGF-1 mediates most of the anabolic and metabolic effects historically attributed to growth hormone: increased protein synthesis, enhanced lipolysis, and improved nitrogen retention. In the 2004 human trial, a single subcutaneous dose of 30, 60, or 90 mcg/kg elevated serum IGF-1 levels by 1.5 to 2.5-fold above baseline, with levels remaining elevated for up to 14 days post-injection.

Two Human Trials, Limited Follow-Up, and a Regulatory Halt

CJC-1295 DAC has been tested in humans in two published clinical trials, both conducted by the compound's developer. The first, a dose-escalation Phase I/II trial published in JAMA in 2004, enrolled 18 healthy adults and evaluated pharmacokinetics, growth hormone secretion, and IGF-1 elevation following single subcutaneous injections of 30, 60, or 90 mcg/kg. Peak growth hormone levels occurred within 24–48 hours and remained elevated for up to one week. IGF-1 levels rose more gradually, peaking around day 7 and remaining above baseline through day 14. No serious adverse events were reported over the 28-day observation period.

The second trial, published in Clinical Endocrinology in 2006, enrolled 47 patients with HIV-associated lipodystrophy and abdominal fat accumulation. Participants received 1–2 mg subcutaneous injections every two weeks for 12 weeks. The study reported statistically significant reductions in visceral adipose tissue (measured by CT scan) and increases in lean body mass compared to placebo. IGF-1 levels remained elevated throughout the dosing period. However, serious adverse events occurred in a subset of participants, including cardiovascular events and one case of congestive heart failure, though causality was not definitively established.

Development was halted in 2007 after the FDA placed a clinical hold on CJC-1295 DAC, citing safety concerns and requesting additional preclinical data. No further clinical trials have been conducted since. The compound is not approved by the FDA, EMA, or any other major regulatory agency, and it remains available only for research purposes.

Animal data is similarly limited. Published preclinical studies in rodents demonstrated dose-dependent increases in growth hormone and IGF-1 following subcutaneous injection, with sustained elevations lasting multiple days. No long-term toxicity studies in animals have been published in peer-reviewed journals.

Dosing, Stability, and the Key Practical Difference from CJC-1295 Without DAC

The human trial data provides the only published dose ranges: 30–90 mcg/kg for single-dose pharmacokinetic studies, and 1–2 mg per injection (administered biweekly) in the lipodystrophy trial. For a 70 kg individual, 30 mcg/kg translates to approximately 2.1 mg. These doses are higher than those used for Sermorelin or Mod GRF 1-29, reflecting the compound's extended half-life and slower absorption kinetics.

CJC-1295 DAC is administered via subcutaneous injection, typically in the abdominal region. The peptide is supplied as a lyophilized powder and reconstituted with bacteriostatic water immediately before use. Once reconstituted, stability data from the manufacturer suggests refrigerated storage (2–8°C) for up to 14 days, though peer-reviewed stability studies are not available.

The most significant practical distinction is between CJC-1295 with DAC and CJC-1295 without DAC. The latter is often referred to as Mod GRF 1-29 or simply "modified GRF 1-29," and it lacks the albumin-binding modification. Without DAC, the peptide has a half-life measured in minutes to hours, not days, and is typically dosed 1–3 times daily at 100–200 mcg per injection. The two compounds are not interchangeable, and research protocols should specify which variant is being used.

Half-life for CJC-1295 DAC is approximately 6–8 days in humans, based on pharmacokinetic modeling from the 2004 trial. This is orders of magnitude longer than native GHRH, Sermorelin (half-life ~10 minutes), or Ipamorelin (half-life ~2 hours). The extended duration eliminates the need for frequent dosing but also complicates safety considerations: once injected, the compound cannot be rapidly cleared, and any adverse effects may persist for the duration of albumin binding.

No published drug interaction studies exist for CJC-1295 DAC. Theoretical concerns include additive growth hormone elevation when combined with other GHRH analogs, growth hormone secretagogues like GHRP-2 or GHRP-6, or direct growth hormone administration. Co-administration with insulin or glucose-modulating drugs could theoretically alter glycemic response, given growth hormone's effects on insulin sensitivity, though this has not been tested.

FAQ

Q: What is the difference between CJC-1295 with DAC and without DAC?

The DAC (Drug Affinity Complex) modification binds the peptide to serum albumin, extending its half-life from minutes to approximately one week. CJC-1295 without DAC (Mod GRF 1-29) requires multiple daily doses, while the DAC version is dosed weekly or biweekly. The two are not interchangeable in research protocols.

Q: How long does CJC-1295 DAC stay in the system?

Pharmacokinetic data from the 2004 human trial showed measurable plasma levels and elevated IGF-1 for up to 14 days post-injection, with peak growth hormone secretion occurring within 24–48 hours. Effective duration of receptor activation is approximately 6–8 days. This is significantly longer than any GHRH analog without albumin binding.

Q: Why was clinical development of CJC-1295 DAC stopped?

The FDA placed a clinical hold in 2007 after serious adverse events, including cardiovascular events, occurred in a trial enrolling HIV patients with lipodystrophy. The hold requested additional preclinical safety data, and development was not resumed. The compound is not approved for therapeutic use and remains available for research purposes only.

Q: Can CJC-1295 DAC be combined with other growth hormone secretagogues?

No published studies have evaluated combination protocols. Theoretically, combining CJC-1295 DAC with growth hormone-releasing peptides like Ipamorelin, GHRP-6, or Hexarelin could produce additive effects on growth hormone secretion, but safety and efficacy have not been characterized in controlled settings. The long half-life complicates dosing adjustments.

Q: What is the evidence quality for CJC-1295 DAC?

Evidence consists of two small human trials (n=18 and n=47) published in 2004 and 2006, both sponsored by the developer, and limited preclinical rodent data. No independent replication studies, long-term safety data, or large-scale controlled trials exist. The compound has not been studied in healthy populations beyond the initial Phase I/II pharmacokinetic trial.

This article is provided for informational and research purposes only. CJC-1295 DAC is not approved by the FDA or any regulatory agency for human therapeutic use, and its long-term safety profile has not been established. Consult a licensed healthcare provider before considering any investigational compound.